| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive and highly-versatile speed detection device capable of detecting speed highly accurately even in an extremely low speed area. SOLUTION: This device includes a latch signal generation part 21 for detecting the edge of an output pulse from an encoder; a rotation direction detection part 32 for detecting a rotation direction based on the detected edge; a rotation direction holding part 33; a time counter 23 for measuring a time synchronously with a speed operation period; data latches 25-1 to 25-4 for holding a time measured value by output from the latch signal generation part 21; an edge change information holding part 29 for detecting an edge change state during the speed operation period, and holding it as edge change information; and a CPU 30A for predicting an edge generated next when the edge is not changed during the speed operation period from the rotation direction and the edge change information, and operating rotational speed of a rotator by using a time correction value corresponding to the edge prediction value, the time measured value in data latches 28-1 to 28-4, and the rotation direction in the rotation direction holding part 33. COPYRIGHT: (C)2009,JPO&INPIT
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